| abstract |
Polyester polyols made from recycled polyethylene terephthalate (rPET) and processes for making them are disclosed. The rPET is heated with a C 3 -C- 10 glycol reactant to give a digested intermediate comprising glycols and a terephthalate component, which comprises 45 to 70 wt.% of bis(hydroxyalkyl)terephthalates, and preferably lesser amounts of terephthalate dimers and trimers. Treatment of the digested intermediate with activated carbon gives a polyester polyol having a color index less than 20. The polyols have desirable hydroxyl numbers, viscosities, appearance, and other attributes for formulating polyurethane products and are a sustainable alternative to bio- or petrochemical-based polyols. |